EP2994302A1

EP2994302A1 - Flat die for a pellet press, pellet press for producing pellets and method for producing a flat die

Info

Publication number: EP2994302A1
Application number: EP14722187.3A
Authority: EP
Inventors: Michael Kluschkewitz
Original assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Current assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Priority date: 2013-05-06
Filing date: 2014-05-06
Publication date: 2016-03-16
Also published as: DE102013104615A1; WO2014180829A1

Abstract

A flat die for a pellet press for producing pellets, preferably from biomass, for use as combustible material in burners, the biomass consisting of cellulosic and/or lignocellulosic fibers, shavings or chips, has a plurality of bores arranged on at least two hole circles to form an annular running surface. Each hole circle has the same number of bores. For each bore of a hole circle an adjacent bore is set off about an angle 2α , and for each bore of a hole circle at least one bore set off by an angle α is arranged on an adjacent hole circle.The invention further relates to a pellet press and to a method for producing a flat die.

Description

Flat die for a pelleting press, a pelleting press for the production of pellets and method for producing a flat die

The invention relates to a flat die for a pelleting press for the production of pellets according to the preamble of claim 1, a

Pelleting press for the production of pellets according to the preamble of

Claim 1 1 and a method for producing a flat die according to the preamble of claim 15. The production of pellets, also called pellets or granules, from fines or compacted and / or molten material is already known. The production of pellets, or wood pellets, from preferably comminuted biomass, such as sawdust, dust or the like is also already well known and is propagated in the field of renewable energy as a forward-looking technology for climate protection, especially in Europe. As raw material is usually chip material from the

used in the wood processing industry, but it is also possible to utilize freshly felled stocks or non-recoverable types of wood or waste in the woodworking industry. For the market of wood pellets for

Supply of small combustion plants in single or multi-family houses is preferably to use pollutant-free base material. Block power plants or special high-temperature furnaces for heat generation and / or for the production of electrical energy (combined cycle power plants) can also cleanly burn small amounts of contaminated material (pellets of chipboard or MDF boards with or without a coating or a coating).

The wood pellets are usually produced in so-called pelleting presses, in which the material to be pressed is pressed by moving and / or active rolling rolls, also called roll-up rolls, through bores of a die. Through the holes, the material (biomass) is formed and discharged as strands from the holes. Under holes In this case, all openings are understood to be made, preferably substantially cylindrical, arranged in a die for passage and shaping of the material. The holes can also larger

Have inlet areas (countersinks) to improve the pressing process and be hardened or have hardened sleeves in the holes.

In the area of the matrices, a distinction is made between flat and ring matrices. On ring matrices run for pressing on the outside or inside rollers, on

Flat dies roll the roller rollers circular (mill construction). The invention preferably deals with flat dies of the latter type, but may also be used with ring dies. Also, the material to be compacted may be not only biomass for incineration in fireplaces, but any pelletable material such as feed or food, coal, plastic or the like.

The possibilities of processing and spreading the biomass, or the post-processing (shredding of the strands, cooling, storage, transport) of the pellets need not be discussed further. Reference is made to the prior art.

Due to the worldwide acknowledged global warming, the industry is forced to accelerate and cheapen the large industrial production of wood pellets. An essential consumable part of the pelleting presses is the flat die itself. By impressing and compacting the biomass on the walls of the bores, high friction values and pressures are generated, which cause the

Erode die holes and increase over time. At the same time, it may happen during the supply of biomass that high-density elements, such as stones, pieces of metal or the like reach the flat die and through the rolling rolls are pressed into the flat die and damage them locally.

In order to remedy local damage or partial wear on a die with the least possible effort or to facilitate replacement of the die with a replacement part, DE 10 2009 047 902 A1 has proposed forming a die as a multi-part die having two or more die segments , It can thus removed a die segment from the die and a new or refurbished used

Matrix segment can be used again without the entire die must be replaced. As a result, the downtime of the pelleting press is kept low.

In this way, although the duration of possible downtimes can be reduced, in this way the occurrence of damage to the die requiring replacement of the die or die segments in the case of a multi-part die is not prevented or reduced.

Especially in pelleting presses, which are designed for the large-scale industrial production of pellets are to achieve the largest possible

Throughput of biomass through the pelleting press and to achieve a correspondingly high production capacity of pellets made high demands on the die. In particular, the die must withstand the very large forces exerted by the rolls to force the biomass through the wells at the desired high throughput. At the same time, the die is often required to achieve as high a yield as possible

Production throughput, the largest possible number of holes, wherein with increasing number of holes, the die itself consists of less material that still absorb and dissipate the forces exerted by the rollers forces. It should be noted in particular that irregularities can form in the biomass to be compacted, for example, because in the residual layer of biomass, which forms on the matrix during operation of the pelleting press, lumps or

Build up clusters, especially because of the front of the rollers

Do not compress and push away biomass quickly and / or not evenly enough. If a roller then passes over such an irregularity, then this can lead to a large part of the force with which the roller exerts a pressure perpendicular to the surface of the die concentrating on the small, restricted area of the irregularity, so that the die is locally closed a very high force is loaded, which can lead to the rupture of the die in extreme cases. To reduce this risk, the die can be made more resistant by, for example, increasing the diameter of the die and / or increasing the thickness of the die, but in turn increasing it accordingly

Plant costs for the pelleting press leads.

There is therefore a conflict of objectives between the requirements of low damage and failure frequency, high production capacity and low system costs. It is therefore an object of the present invention to provide an improved flat die, an improved pelleting press and a method for

To provide a flat die, which allows an improved solution of the conflict of objectives, especially for a given production capacity and size of the plant can achieve a reduced damage and failure frequency.

These and other objects of the invention are achieved with a flat die for a pelleting press for producing pellets according to claim 1, a pelleting press for producing pellets according to claim 11 and a method for producing a flat die according to claim 15. Further preferred embodiments are in the corresponding

dependent claims set forth.

As a solution, a flat die for a pelleting press is specified for the production of pellets, preferably from biomass for use as fuel in fireplaces, the biomass consists of cellulose and / or lignocellulosic fibers, chips, or chips, the flat die having a plurality of holes which are arranged lying on at least two bolt holes to form an annular tread. There are formed on each bolt circle in each case an equal number of holes, wherein for each hole of a bolt circle an adjacent hole is offset by an angle 2a and at least one offset by an angle α hole is arranged on an adjacent pitch circle for each hole of a bolt circle. The angle α should preferably be defined as the opening of the circular section, which is determined by two center line through the centers of offset holes on an adjacent hole circle.

By the same number of holes are provided on each bolt circle, which are arranged substantially uniformly spaced, and by the holes of adjacent bolt circles are offset from each other, a very uniform arrangement of the holes can be achieved. In particular, the many holes formed in the flat die have an in

Essentially the same, uniform web distance to each other. Therefore, when a roller of a pelleting press rolls over the running surface formed by the bores, the biomass can be pressed very evenly and the risk of damage to the flat die due to uneven pressing or displacement of the material to be pressed is reduced. Preferably, the flat die is formed from a plurality of die segments. By splitting the flat die or the rolling surface into several parts can be on expensive devices and corresponding

Assembly effort to remove a full die are waived. If the flat die is, for example, quartered, accessibility to the production space of about 55 to 60 ° is sufficient to get it out of the pelleting press and to insert a new one. The disassembly of drives, shafts or other machine elements can be largely avoided. This is particularly preferably applicable to pelleting presses, as disclosed in DE 10 2009 051 481 A1, which can have a multiplicity of pressing devices distributed over a flat die.

It is preferred that the abutting edges of two adjacent

Matrizensegmente in the region of the tread are formed so that the intersections of a joint edge with two mutually adjacent hole circles are offset by the angle α. More preferably, it can be provided that two adjacent, arranged on both sides of a joint edge holes of a same bolt circle are offset by an angle 4a. In this way, an improved and more uniform rolling of the roller at the abutting edges of the die segments can be achieved.

Preferably, the Flachmatrize a number M matrix segments, and there are formed on each hole circle a number m holes, wherein the angle α has a value of:

360 °

2 (M + m) 'so that a number of holes on a circular arc portion of a bolt circle formed by a die segment is given as a natural number I: and that, starting from a straight line extending from the center of the

Flat die extends in the radial direction, the holes are arranged at angles: γ = a (2i + (h - 1) + jl + 1)), where h is the number of the respective pitch circle (ki, k ₃ , ...) , and i and j pass through the values i = 0, 1, 1-1 and j = 0, 1, M-1. If the die consists only of a die segment M, then the value i must pass through the values i, ..., i for the above arrangement of the holes.

For example, 12 die segments and 6 bolt circles may be provided, 168 holes are formed on each bolt circle and the angle α = 1 °.

Further preferably, it can be provided that in an outer edge region and / or an inner edge region of the flat die, the abutting edges extend along a straight line extending from the midpoint in the radial direction. In this way, a stop can be formed which facilitates the assembly of die segments. Next you can

Centering be provided to facilitate the addition of the

Die segments together.

Preferably, two adjoining die elements are connected by at least one, the abutting edge cross brace. This allows a fast and secure mounting of the die elements. Preferably, the distance d between two holes of two adjacent hole circles is approximately given as: d = r sin (a), where r is the radius of one of the two pitch circles, the mean of the radii of the two pitch circles, or the mean of the radii of all the pitch circles. With this Choice of the distance between two adjacent hole circles a geometrically very uniform arrangement of the holes can be achieved. In order to make the most accurate possible consideration of the hole circles extending in the outward direction of the flat die, the value r can be taken into account as the mean of the radii of the two adjacent hole circles. Since the value d is calculated on the basis of a circle of holes, and thus the radius of the next circle of holes is first determined, this generally leads to the necessity of iteratively determining the value r. It can therefore also be provided to simplify the calculation, instead take the radius of one of the participating bolt circles as the basis of the calculation. Depending on the requirements and the size of the flat matrix, in particular for very large radii and in comparison to very small distances between them

Hole circles may also be designed to select only a nominal value of a radius, for example, corresponding to the radius of a central bolt circle or the half of the effective diameter of the flat die in order to carry out the calculation based on this.

As another solution, a pelleting press for the production of pellets is given, preferably from biomass for use as fuel in fireplaces, the biomass of cellulose and / or lignocellulosic fibers, chips, or chips, and wherein in the pelleting press at least one Flachmatrize with a plurality of holes for pressing the biomass, at least one roller rolling on the die and at least one drive device for the flat die and / or the roller are arranged.

Preferably, it may be provided that in support of

Matrizensegmente opposite the roller at least one support device is arranged. The support device may have at least one opening for the passage of the emerging from the holes of the flat die pellets. By the support device is thereby ensured that the deflection of the flat die remains in a manageable framework and has no consequence on the operation during pelleting. In support of the

Flat die, the support device may be arranged substantially at the abutting edges of the die segments and / or joint-overlapping at the edges of the flat die. The latter is preferably useful for narrow flat matrices. Preferably, however, just the abutting edges of the die segments are supported by the support device so that it can not come to deflections by the heavy or even several heavy rollers.

Preferably, therefore, the flat die of a high-strength,

especially low-wear, material are manufactured. Even hardened materials are possible. Prone to embrittlement or fatigue

Flat dies can be supported with an intermediate layer to the support, which provides excellent damping against harmful

Vibrations results. Nevertheless, the teaching of the invention should show the possibility of very hard, or even brittle materials, or partially or

through-hardened materials respectively tool steels, to be used as a flat die. In particular, the present invention makes it possible to make the flat die itself as thin as possible, about 30 to 100 mm thick. Since this is sufficiently supported by the support device, it can also be a very expensive material or a hardened steel or a very hard steel, or stainless steel, can be used. As a further solution, a method for producing a flat die for a pelleting press for the production of pellets, preferably from

Biomass for use as fuel in fireplaces, the

Biomass from cellulose and / or lignocellulosic fibers, chips, or chips, wherein the flat die has a plurality of holes arranged on at least two hole circles (ki, k ₂ , ...) lying are to form a kreishngförmige running surface, wherein the holes on the respective bolt circle (ki, k ₂ , ...) at the angles γ = a (2i + {h - 1)), where h is the number of corresponding to the circle of holes (ki, k ₂ , ...), and i passing through the values i = 0, 1, ..., I, where I is the number of holes on a pitch circle (ki, k ₂ , ... ).

Preferably, in a flat die, which consists of several

Die segments, the intersection for the abutting edge between two die segments at the angle δ = α 21 + (h - 1) + 2j l + 1)), where h is the number of the respective pitch circle (ki, k ₂ , ... ), where j passes through the values j = 0, 1, M-1, and where I is the number of holes on a circular arc portion of a pitch circle (ki, k ₂ , ...) of a die segment and M is the number of die segments, wherein no hole is arranged at the abutting edge.

Further advantageous measures and embodiments of the subject matter of the invention will become apparent from the following description with the drawing.

Show it:

1 is a plan view of a multi-part flat die,

Fig. 2 is a cross-sectional view of a flat die and arranged underneath

Support device in a pellet press with revolving roller, and Fig. 3 Connection of die segments by staples. 1 shows a flat die 4 comprising a plurality of die segments 7 to 7 ". The flat die 4 has a multiplicity of bores 13 which are arranged lying on a plurality of hole circles ki, k ₂ ,

To form running surface 19 over which run during operation of a pelleting press one or more rollers 5 and roll, as indicated by the arrow for the

Unwinding direction 6 indicated.

2, in a pelleting press 3 biomass 1 is scattered during production on a flat die 4 and pressed by means of the rolling roller 5 through the holes 13 which are arranged in the flat die 4 in the direction of the passage direction 12. On the tread 19, also called

Rolling surface can be designated, it can form a residual layer of the biomass 1 after passing through the roller 5. After passing through the holes 13 strands or pellets 10 form when leaving the

Drill holes 13 that require further treatment or onward transport. The holes 13 of the flat die 4 preferably correspond with one or more openings 8 of a support device 9, on which the flat die 4 rests. It is irrelevant whether the flat die 4 is moved, or whether the roller 5 is moved and / or the roller 5 in addition to the direction of movement of the flat die 4 is still a self-propelled

Own rotation has.

With reference back to the Fig. 1 it can be further seen that on each of the hole circles ki, k ₂ , ... are formed in each case an equal number of holes 13, wherein the holes 13 of a bolt circle within a die segment 7 to 7 "in each case an angle 2a are arranged offset, wherein further the bores 13 of each adjacent hole circles ki, k ₂ , ... are arranged offset by an angle α .. In this way, advantageously, a uniform, dense packing of the holes 13 in the die 4 reaches become. Adjacent die segments 7, 7 ', 7 ", ... touch each other

corresponding abutting edges 2, which, as shown in Fig. 1, are formed so that they are substantially curved in the region of the tread. The waveform is chosen so that, starting from an intersection of the abutting edge 2 with a bolt circle ki, k ₂ , ... the Schnittpunt the joint edge 2 with an adjacent pitch circle ki, k ₂ , ... offset by the angle α , Accordingly, in Fig. 1, two adjacent

Holes 13 which are arranged on a same circle of holes ki, k ₂ , ... and which enclose between them the abutment edge 2, offset by an angle 4a.

In the example of FIG. 1, in which the flat die 4 has a number M = 3 die segments 7, 7 ', 7 ",... And a number m = 15 bores 13 on each hole circle ki, k ₂ , are formed, the angle is a:

360 ° 360 °

a = = = 10 °.

2 (M + m) 2 (3 + 15)

The number I of holes 13 on a circular arc section of a

Bolt circle ki, k ₂ , which is formed by a die segment 7, 7 ', 7 "..., is given for the example of FIG. 1 as:

15

~ Μ ^~ Ύ ^~

If an imaginary center straight S is assumed, which differs from the

Center point Z of the flat die 4 extends in the radial direction, then the position of the holes can be specified as the intersections of the center point Z rotated by the angle γ center point straight S with the respective hole circles ki, k ₂ , where the angles γ are given as: γ = a (2i + (h-1) + 2j 1 + 1)), where h is the number of the respective pitch circle ki, k ₃ ,..., that is, h = 1 for the first pitch circle k-1, h = 2 for the second pitch circle k _2, and so on. The variables i and j go through the values i = 0, 1, 1-1 and j = 0, 1, M-1. In the example of FIG. 1, with I = 5 and M = 3, values for the angles γ of the bores 13 of the first pitch circle ki, and consequently h = 1, of 0 °, 20 °, 40 °, 60 ° are obtained , 80 °, 120 °, 140 °, 160 °, 180 °, 200 °, 240 °, 260 °, 280 °, 300 ° and 320 °.

Similarly, the position of the intersections of the abutting edges 2 with the pitch circles ki, k ₂ , ... can be described as the intersections of the center point S which is rotated by the angle δ around the center Z with the respective pitch circles ki, k ₂ , the angles δ are given as: δ = α 21 + (h-1) + 2j l + 1)),

where h is again the number of the respective pitch circle ki, k ₃ ,..., I denotes the number of holes 13 on a circular arc section of a

Pitch circle ki, k ₂ , which is formed by a die segment 7, 7 ', 7 ", ..., designated, and the variable j the values j = 0, 1, M-1 passes through.

In the example of FIG. 1, with M = 3, values for the angles δ of the points of intersection of the abutting edges 2 with the first pitch circle k-i, and consequently h = 1, of 100 °, 220 ° and 340 ° are obtained.

As will be readily apparent, the example of FIG

Holes 13 and the points of intersection of the abutting edges 2 with the respective further pitch circles k ₂ to k for the angles γ and δ values which are opposite to the values of the angles γ and δ for the first pitch circle ki by the angle α = 10 ° for the second pitch circle k ₂ , are increased by the angle 2a = 20 ° for the third bolt circle k ₃ , and by the angle 3a = 30 ° for the fourth bolt circle k. For two adjacent hole circles ki, k ₂ , ... is therefore the location of the holes and the intersections of the abutting edges 2 with the pitch circles ki, k ₂ , ... offset by an angle α in each case.

The values mentioned above with reference to the example of Figure 1 are merely exemplary and not limiting, and any other values may be chosen. For example, 12 die segments and 6 bolt circles may be provided, 168 holes are formed on each bolt circle and the angle α = 1 °. Preferably, the distance d between two holes of two adjacent hole circles ki, k ₂ , ... is approximately given as: d = r sin (a), where r is chosen as the pitch circle radius n, r ₂ , outer of the two adjacent pitch circles ki, k ₂ , or an average value of the pitch circle radii η, r ₂ , ... of the two adjacent pitch circles ki, k ₂ , or an average of the pitch circle radii n, r ₂ , ... of all pitch circles ki, k ₂ ,... Of the flat die 4. It is also possible to choose the value r as a nominal radius used to construct the flat die 4, such as for the center of the tread 19. As described above, the abutting edges 2 in the region of

Tread 19 a curved course. The curved course can extend up to an inner and an outer lateral edge of the

Flat die 4 extend. However, as shown in FIG. 1, it is preferred that the abutting edges 2 in an outer edge region 21 adjoining the running surface 19 and / or inner edge region 22 of the flat die 4 are designed to extend along a straight line extending from the center Z in the radial direction ,

For connection and mechanical attachment of the die elements 7, 7 ', 7 "with each other brackets 23 may be provided, as shown in FIG. 3, which overlaps the abutting edge 2 between two adjoining matrix elements 7, 7 ', 7 "

There are fundamental efforts to produce a flat die, preferably from a single steel. For example, a so-called knife steel such as the X46C 3 (1 .4034), which with its martensitic structure and freedom from rusting is a good compromise between corrosion resistance, service life and brittle fracture susceptibility, is particularly suitable for this purpose.

The pelleting press 3 is particularly preferably suitable for the production of pellets 10 from biomass 1 for use in fireplaces, but can also be safely used in other areas.

List of Reference P1451:

1 biomass

2 abutting edge

3 pelleting press

4 flat die

5 roller

6 rolling direction

7 die segment

8 breakthrough

9 support device

10 pellets

12 passage direction

13 holes

19 tread

21 edge area outside

22 edge area inside

23 bracket

Z center point

s midpoint straight d distance

ki, k ₂ , k ₃ , k ₄ hole circle r- ₁ , r ₂ , Γ3, r circle radius a, Y, δ angle

Claims

claims

A flat die (4) for a pelleting press (3) for producing pellets (10), preferably from biomass (1) for use as fuel in fireplaces, wherein the biomass (1) consists of cellulose and / or lignocellulosic fibers, chips, or shavings, the flat die (4) having a plurality of bores (13) arranged on at least two pitch circles (ki, k ₂ , ...) to form an annular tread (19),

characterized in that on each bolt circle (ki, k ₂ , ...) in each case an equal number of holes (13) are formed, for each hole (13) of a bolt circle (ki, k ₂ , ...) an adjacent hole ( 13) is arranged offset by an angle 2a, and (for each well 13) of a hole circle (ki, k _2, ...) at least one at an angle α offset bore (13) on an adjacent hole circle (ki, k ₂ , ...) is arranged.

2. Flat die (4) according to claim 1, characterized in that the flat die (4) has a plurality of die segments (7, 7 ', 7 ", ...) which form the running surface (19).

3. flat die (4) according to claim 2, characterized in that the abutting edges (2) of two die segments (7, 7 ', 7 ", ...) in the region of the running surface (19) are formed so that the intersections of a joint edge (2) with two mutually adjacent hole circles (ki, k ₂ , ...) are offset by the angle α.

4. flat die (4) according to claim 2 or 3, characterized

characterized in that two adjacent, both sides of a

Enclosed edge (2) arranged bores (13) of the same circle of holes (ki, k ₂ , ...) are offset by an angle 4a. Flat die (4) according to one of claims 2 to 4, characterized ge net I net that the flat die (4) a number M

Has die segments (7, 7 ', 7 ", ...),

in that a number of m bores (13) are formed on each circle of holes (ki, k ₂ ,...) such that the angle .alpha. has a value of:

360 °

a ^~ 2 (M + m) that a number I of holes (13) on a circular arc portion of a bolt circle (ki, k ₂ , ...), of a die segment (7, 7 ', 7 ", ...) is formed, given as:

m and that, starting from a center line (S) which extends from the center (Z) of the flat die (4) in the radial direction, the bores (13) are arranged at angles: γ = a (2i + (h - 1 ) + jl + 1)), where h is the number of the respective pitch circle (ki, k ₂ , ...), and where i and j pass through the values i = 0, 1, 1-1 and j = 0, 1 , M-1.

Flat die (4) according to one of claims 2 to 5, characterized ge net i net net, that the flat die (4) 12 die segments (7, 7 ', 7 ", ...) and 6 bolt circles (ki, k ₂ ,. ..), on each bolt circle (ki, k ₂ , ...) 168 bores (13) are formed and the angle α = 1 °.

Flat die (4) according to one of claims 2 to 6, characterized ge net I net that the abutting edges (2) in an outer edge region (21) and / or an inner edge region (22) along a from the center (Z) extending in the radial direction

Center straight (S) are formed extending.

8. Flat die (4) according to one of claims 2 to 7, d a d u r c h characterized in that two adjacent

Matrizenelemente (7, 7 ', 7 ", ...) by at least one, the abutting edge (2) cross-brace (23) are connected.

9. flat die arrangement (4) according to one of claims 1 to 8,

wherein a distance (d) between two adjacent pitch circles (ki, k ₂ , ...) is given as: d = r sin (a), where r is chosen as the radius of the inner or the outer of the two adjacent pitch circles (ki , k ₂ , ...), or an average of the radii of the inner and the outer of the two adjacent pitch circles (ki, k ₂ , ...), or an average of the radii of all the pitch circles (ki, k ₂ , ... ).

10. Flat die (4) according to one of claims 2 to 7, d a d u r c h

in that one or more centering bores are provided for joining the die segments (7, 7 ', 7 ", ...) to one another.

Pelleting press (3) for producing pellets (10), preferably from biomass (1) for use as fuel in fireplaces, the biomass (1) consisting of cellulose and / or lignocellulosic fibers, shavings or chips, and wherein in the pelleting press (3) at least one die (4) with a plurality of bores (13) for pressing the biomass (1), at least one rolling on the die roller (5) and at least one drive device for the die and / or the roller (5) are arranged,

characterized in that

the die is a flat die (4) according to one of claims 1 to 10.

12. pelleting press (3) according to claim 11, d a d u r c h

characterized in that for supporting the die segments (7, 7 ', 7 ", ...) relative to the roller (5) at least one support device (9) is arranged, and the support device at least one opening (8) for the passage of the bores (13) of the die (4) having exiting pellets (10).

13. pelleting press (3) according to claim 12, characterized

in that, in order to support the die segments (7, 7 ', 7 ", ...), the support device (9) substantially at the abutting edges

(2) of two die segments (7, 7 ', 7 ^" , ...) is arranged.

14. pelleting press (3) according to one of claims 11 to 13, d a d u r c h characterized in that the flat die (4) and / or the

Supporting device (9) in parts or fully hardened and / or made of hardened material.

15. A method for producing a flat die (4) for a pelleting press

(3) for producing pellets (10), preferably from biomass (1) for use as fuel in fireplaces, the biomass (1) consisting of cellulose and / or lignocellulosic fibers, shavings or chips, the flat matrix (4 ) a variety of

Holes (13) which are arranged lying on at least two hole circles (ki, k ₂ , ...) to form an annular raceway (19), characterized in that the bores (13) on the respective bolt circle (ki , k ₂ , ...) at the angles γ = a (2i + {h-1)), where h is the number of the respective pitch circle (ki, k ₂ , ...), and i is the Values i = 0, 1, ..., I passes through, where I is the number of holes (13) on a pitch circle (ki, k ₂ , ...). A method according to claim 15, characterized in that in die segments (7, 7 ', 7 ", ...) of the section for the abutting edge (2) between two die segments (7, 7', 7", ...) in the Angle δ = α 21 + (h-1) + 2j 1 + 1)), where h is the value of the respective pitch circle (ki, k ₂ , ...), where j is the value j = 0, 1 , M-1 passes through, and where I is the number of holes (13) on a circular arc section of a

Bolt circle (ki, k ₂ , ...) of a die segment (7, 7 ', 7 ", ...) and M is the number of die segments and that on the abutment edge (2) no hole is arranged.